cdwilson
commented
3 years ago Just saw this note in the docs when I was trying to figure out why the overage wasn't affecting the "Can Build" value:
Consider the request above as a feature request for when the overage becomes functional in the future 😁
Currently InvenTree supports a single "overage" field:
In PCBA manufacturing, this "overage" is typically specified by the factory as three separate requirements: "minimum quantity", "leader", and "attrition" (see this excellent article from Worthington Assembly for more details)
When loading parts into a pick & place machine, the feeders typically require a minimum length of "leader tape" which is wasted when setting up the machine. This "leader" is typically a fixed value for each component type (e.g. 50 extra parts).
Then, when the pick & place is actually placing components, there is a separate "attrition" overage which is typically specified as a percentage of the total number of components to account for machine rejections, dropped parts, etc (e.g. 25% attrition). This attrition can also be specified as a fixed value.
Finally, many manufacturers require a minimum quantity of parts that must be provided, irrespective of the leader & attrition values. For example, if Quantity=100, Leader=10, and Attrition=25%, the required number of parts would be
10+(100*1.25)=135.However, if the manufacturer has a minimum quantity requirement of 200, the minimum number of parts to be purchased for the build would be 200. On the other hand, if Quantity=1000, Leader=10, and Attrition=25%, the required number of parts would be10+(1000*1.25)=1260.It would be nice if the BOM item in InvenTree could support the following new fields in addition to the existing overage field:
Some examples for reference: https://www.protoexpress.com/pcb/wp-content/uploads/2019/08/assembly-kitting-guidelines.pdf https://www.4pcb.com/Assembly%20Requirements%20(3-1-2017).pdf https://www.worthingtonassembly.com/consigned-material